Wired radio receiving apparatus



March 2 ,1926. 1,575,340

. C- W- HOUGH v WIRED RADIO nscmvme APPARATUS Fil ed Feb. 25, 1924 3 Sheets-Sheet 1 INVENTOR March" 2 1926. 1,575,340 c. w. HOUGH WIRED RADIO RECEIVING APPARATUS Filed Feb. 1924' x 3 Sheets-Sheet 2 INVENTOR March 2", 1926.

C. W. HOUGH WIRED RADIO RECEIVING APPARATUS Filed Feb. 25, 1924 3 Sheets-Sheet 5 INVENTOR W Mir f BY Q, %,M' 7% ATTORNEYS UNITED STATES.

. Patented Mar.

cannon w. Hones; or BOONVILLE, 1\TEW PATENT OFFICE.

YORK, ASSIGNOR TO WIRED RADIO, INC., 01' NEW YORK, N. Y. A CORPORATION OF 'DELAWARE.

wrann RADIO sncmvme Arrmrus.

' A .1ip1ication filed February To all concern:

' Be it known that I, CuN'ron WQIIOUGH, a citizen "of the United States, residing at the f scription of the invention", such as W111 en--- Boonvi'lle, in the county of Oneida, State of New York, have invented certain new and useful Improvements ,in- Wired RadioReceiving Apparatus; and I' do hereby declare lowing to be a full,-clear, and exact deable others skilled 'in the art to which it appertains to make and use the same.

. mission lines of fairl hi h voltage-for ex ample, 110 volts, n t e construction ofapparatus of this character it is necessary to carefully ard against the possibility of electrical s ocks to the subscribers of the broadcasting. service as well as to guard against fire hazard.

Rece vmg apparatus of the character.re-.

' ferred tp is usually distributed on a monthly rental basis instead of'by outright sale and for this reason it is necessary to take precautions againstthe apparatus being tampered with by the subscribers.

The) principal objects of this invention are, therefore to provide a wiredwireless receiving apparatus in whichall danger of electrical shock bein transmitted to the subscriberis' obviated; in which the fire hazard is reduced to a minimum; and in which the more delicate electrical elements and connections are inaccessible to the subscriber. According to the preferred-embodiment of this invention as illustrated in'the accompanying drawingsand the detailed descrip tion hereinafter, all of the electrical ele-' ments and their connections, with the single exception of a fixed crystal detectorgare mounted and completely enclosed withina receptacle which 1s so constructed that it is practically inaccessible to the subscriber. The circuit arrangement comprises a primary circuit and asecondary clrcuit which are inductively associated- Theterminals 25 1924. Serial No. 694,817.

of the primary circuit are arran ed to be connected across an electric light ine while the secondary circuit includes the telephone receivers. In order to prevent the relatively high voltage from the electric light line reaching the telephone receivers and thus.'

subjecting the subscriber to danger of being shocked, the two circuits, that is primary and secondary, are separated by means of a partition of dielectric material of substantial thickness which is capable of withstanding many times the voltage on the -electric light line. For the purpose of guarding a ainst fire hazards, the inductance coil inclu ed in the primary circuit is so designed that in the event of its becoming connected directly across the electric light line it willquickly burn out like a fuse. There is therefore, no danger of a substantial amount of heat being developed in this coil such-as would be likely to result in fire.

Other features of this invention reside in the details of construction all of which are clearly described hereinafter.

Referring to the accompanying drawings, Fig. 1 is an elevational view of a wired wireless receiving apparatus in accordance with the preferred embodimentof this invention,

.Fig. 2 is a plan view of the apparatus shown in Fig. 1, I

Fig. 3 is a vertical cross-sectional viewof the apparatus. taken along the line 3-3 of 7 Fig. 4 is a vertical cross-sectional view taken along the line 4-4 of Fig. 3, i Y Fig. 5 is a vertical cross-sectional view taken along the line 5-5'of Fig. 6,

Fig. 6 1s a vertical cross-sectional view taken along the line 6.6of Fig. '5, :Fig. 7 is a plan view of the apparatus with the cover of. the receptacle removed.

Fig. 8 is a 12m view similar to Fig.2 except that it s ows o ly the topof-thereceptacle-the control. tector being omitted.-

Fig. 10 is a fragmentary elevational view showmg the crystal detector and Fig. 11 is a circuit diagram. The circuit arrangement here employed as. shown in Fig. 11 comprises a time circuit and a secondarycircuit. e primary circuit comprises an inductance coil al and crystal idea 1 and a variable condenser 2 while the secl ondary circuit comprises an inductance coil 3, crystal detector 4, fixedcondenser 5, and

'cover 8, both of which are preferabl made of pressed sheet metal. The crystal etector is mounted on the outside of the receptacle for the reason that it ma be desirable or necessary for the subscriber to change it from time totime should it get out of adjustment.

The base 7 is made in two arts, 7 and 7", the'first of which forms a al'se bottom as clearly shown in Figs. 3 to 6 inclusive.

Three partition members', 9, 10 and 11 each consisting ofaplate of dielectric material such as bakelite are securedto the false bottom 7* by means of screws 12 as may be. clearly seen from an examination of Figs; 3. to 6 inclusive; the screws 12 are inaccessible from the exterior of the recepings 1 and 1 respectiveliy tacle because of the ,fact'that the heads are concealed by the'base member 7". Members 7 and "7 are secured together by means-of rivets. 13, and are held in proper spaced relation by separators 14. Inductance coils 1 and 3 of the primary and secondary circuits respectively, are disposed on opposite sides of the partition 9 in inductive relation one to the other. These coils are preferably of the honeycomb type having central openand are supported on rectangular pieces 0 dielectric material 15 and 16 which are secured to partitions 10 and 11 b means of roundhead screws 17 and 18. Each of the partitions 10 and 11 is provided with two tapped holes 19 and 20, one above the other, into eitherof which screws 17 and 18 may. be inserted. Additional tapped holes? may be provided if desired. These holes serve to permit the coils 1 and 3 bein moved up and down for changing the in uctive coupling therebetween.

The lead-'n cord 21, to one end of whic the screw plug '22 is attached, is assed through an insulating bushing 23 to t e interior of the receptacle and is made fast to partition 10 in the manner clearly shown in Figs. 3 and 5. j

Theprimary variable condenser 2 is of the rotary type and is secured to the tops of the partition members 9, 10 and 11. The

plates oft-his condenser are. completely'enclosed within a casing of insulating material and a rotatable shaft 24 for operating the condenser extends to the outside of the cover 8. A knob and dial 25 is secured to the end of shaft 24 by means of a-scrw 26. When the screw 26 isin place the aperture 27 in the knob 25 thru wh ch it asses is filled with "sealing wax or some ot er suitable compoundsothat the end or the screw is not subscriber.

accessible.- The cover 8 of the rece tacle' is so formed that it underlies the d1al 25 and is so arranged that a tool or wire cannot be readily passed under the dial to the interior of the ap aratus. In order to remove the cover 8 rom the base 7 and thus gain access to the interior of the apparatus, I it is necessary to first remove screw 26 and then the knob and dial 25 after which the cover -8 may be lifted off the base. TBy reason of the fact that the aperture 27 is sealed up with wax of the same color as-the lmob 25 the method of gaining access to the interior of the apparatus is concealed from the The two conductors of cord 21 59 are' connected respectively to one terminal;

of condenser 2 and to one terminal or in ductance coil 1 while the remalning terminals of coil 1 and condenser 2 are connectedtogether. The fixed condenser 5 is provided 55 with a pair of Faunestock clips connected to its terminal and to which the tips of the telephone cord are attached. Condenser ,5 is secured to partition 11 by means of bolt 29 and nut 30. The metal straps 3'1 and 32' to, the upper ends of which the fixed crystal detector 4 is attached are secured to partition 11 by means of bolts 29 and 33. Since the bolts 29 and 33 pass throughboth straps 31 and 32 it is necessaryto insu- 5 late these bolts from at least one of the straps. This is accomplished by providing insulating bushings and washers between the straps and bolts.

In order to prevent short circuiting straps 31 and 32 through the metal cover 8, soft rubber sleeves 34 and 35 are provided. These sleeves may be easily slipped ofi the straps whenever the cover 8 is to be removed.

In operation, screw plug 22 is inserted in are transmitted. The secondary circuit is not tuned in so far as it is affected by 1 5 the tuning of the primary circuit.

Inductance coil-1 is of relatively fine wire so that in the event of a break-down'of condenser 2 the current which would pass will quickly burn out coil 1 and open the primary circuit. The possibility of any dangerous voltage bein transmitted to the secondary circu1t and t ence to the telephone head set is obv1ated by 'thedprqvision of partition 9 which separates-th primary and secondary circuits. 'Thispartition is preferably of-a good dielectric material and is of... ample thickness to withstand a muchgreater -'volt-' age than is ever ,likely-to-be applied to-the p m ty c rcu 31 1. In high frequency signal receiving apparatus, a receptacle comprising a base'and acover therefor, a variable electrical devicemounted' within said receptacle, a-rotat'able shaft for said device extending to -the. 'e'xterior of said receptacle, .a knob and dial secured to said shaft, said dial beingundercut at its lower face and said cover having 'an annular depression'inthe top thereof terminating in,a'n annular beadextending upwardly to a position with'inthe undercut face of said'dial for obstructing a straight line passage between said dial and cover, said knob and dial being operable to prevent the removal of said cover from said base,,said

so t at it is inaccessible from the exterior of the receptacle. v

.2. In high frequency signal receiving ap-l paratus, a receptacle comprising a base, a cover fitting said base and forming there:-

,with a substantially enclosed receptacle, a

partition of dielectric materialsu'pported on said base and enclosed withinfsaid recep- 25 tacle, a primary circuitjc'omprisingan inductance coil, said coil being mounted on one side-of said partition, asecondary circuit comprising-a second inductance coil mounted on the other side of said partition in inductive relation to said first-mentioned inductance coil, a variable electrical device having a rotatable shaft, said device'being mounted within said receptacle with said shaft extending to the exterior thereof through an aperture in said cover, a dial secured to the exterior end portion of said shaft, said dial overlying a portion of said cover, thereby preventing removal of said cover from said base, attachingmeans for securing said dial to said shaft, and means for enclosing said attaching means to prevent unauthorized tampering therewith.-

3. In high frequency signal receiving 'ap} paratus, areceptacle comprising a base hav-I ing a bottom member and a false bottom.

, member, partitions of dielectric material mounted on saidbase and secured-tosaid false bottom member by means of screws which extend throughsaid false bottom member, said bottom member covering said screws so as to prevent access thereto, elec v trlcal elements mounted on said partltions,

said elements including an adjustable element having a rotatable shaft, said receptacle including a cover which fits on said base and cooperates therewith 'to form a substantially complete enclosure for said electrical elementsfsaid shaft projecting through an aperture in said cover to the exterior thereof, a'dial' mounted on. .the end portion of said shaft and overlying a por-' tion of said cover, means for securmgsaid dial to said shaft, said dial having an aper- L 'ture to permitythe insertion of said means,

receftacle completely enclosing said device said a erture being sealed after the inserand variable. tuning means supported by said partition members and operable from the exterior of said casing.

5. A wired radio receiving apparatuscomprising in combination a metallic casing, an insulated entrance for a power sup- 'ply line .in one-wall of said casing, a palr 'of radially extending dielectric partitions within said casing, a diametrically disposed dielectric partition member separating the adjacent ends of said partitionmembers, a

primary coil carried by one of said first I mentioned partition members, a secondary coil carried by the other of said first mentioned partition members, said coils being substantially insulated one from the other by said diametrically extending partition member, andtuning apparatus carried by the extremities of said partition members and operable from the exterior of said casmg, a

insulated entrance for a power supply line carried in one wall of sai casing, a pair of radially positioned dielectric partition members within said casing, a diametrically disposed partition member extending between adjacent ends of said pair of artition members, vertically adjustable 00' supports carried by adjacent ends of said pair of partition' members and inductance coils positloned on the adjacent ends of said pan of partition members and arranged to be selectively set in position with respect .to each other, tuning apparatus carriedby said partition members, and means for operating said tuning apparatus from the exterior of said casing.

6. Wired radio receivingapparatus com- .PIlSlJlg 1n combination a metalllc casing, an

'7. Wired radio receiving apparatus comprising in combination a fire-proof casing,

an insulated entrance for power line conductors in one wall of said casing, a primary circuit, a secondary circuit, each of said circuits includin an inductance coil and said primary circuit having a. condenser in series with the inductance coil'therein, a pair of dielectric artition members radially positioned wit in said casin a diametrically disposed partition mem r positioned between adjacent ends of said pair of partition members, said pair of partisaid primary circuit the inductance therein tion members carrying said inductance coils becomes ruptured for protecting. said wired 10 at their adjacent edges substantially insu- .r'adio receiving apparatus against destruclated one from the other by said diametritive effects from the current existent in said callyrextending. partition member, the inpower supply line.

ductance disposed in said primary circuit In testimony whereof I aflix my signahaving such value that upon failure of the ture. dielectric properties of the condenser in the CLINTON W. HOUGH. 

